• Title/Summary/Keyword: STORM

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The Vulnerability of the Reclaimed Seashore Land Attendant Upon Storm Surge/Coastal Inundation (해일/범람에 따른 해안 매립지의 취약성)

  • Kang, Tae-Soon;Moon, Seung-Rok;Nam, Soo-Yong;Shim, Jae-Seol
    • Journal of Ocean Engineering and Technology
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    • v.24 no.1
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    • pp.68-75
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    • 2010
  • Recently, the intensity and frequency of typhoons have been on the increase due to unusual weather phenomena and climate change. In particular, on September 13, 2003, typhoon MAEMI (0314) caused heavy damage in the provinces of Busan and Gyongnam, but also provided an opportunity to perform a variety of studies on storm surge. According to investigation reports on the damage resulting from typhoon MAEMI, the areas where coastal inundation occurred were located in reclaimed land under coastal development. In this study, through an image data analysis of historic and present day typhoons affecting Masan, we found that the inundation damage areas corresponded to reclaimed lands. Therefore, using the area around Busan, including the southeastern coast of Korea where typhoons lead to an increased storm surge risk, we performed a storm surge/inundation simulation, and examined the inundation effect on reclaimed land due to the intensified typhoons predicted for the future by climate change scenarios.

Regional Extension of the Neural Network Model for Storm Surge Prediction Using Cluster Analysis (군집분석을 이용한 국지해일모델 지역확장)

  • Lee, Da-Un;Seo, Jang-Won;Youn, Yong-Hoon
    • Atmosphere
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    • v.16 no.4
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    • pp.259-267
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    • 2006
  • In the present study, the neural network (NN) model with cluster analysis method was developed to predict storm surge in the whole Korean coastal regions with special focuses on the regional extension. The model used in this study is NN model for each cluster (CL-NN) with the cluster analysis. In order to find the optimal clustering of the stations, agglomerative method among hierarchical clustering methods was used. Various stations were clustered each other according to the centroid-linkage criterion and the cluster analysis should stop when the distances between merged groups exceed any criterion. Finally the CL-NN can be constructed for predicting storm surge in the cluster regions. To validate model results, predicted sea level value from CL-NN model was compared with that of conventional harmonic analysis (HA) and of the NN model in each region. The forecast values from NN and CL-NN models show more accuracy with observed data than that of HA. Especially the statistics analysis such as RMSE and correlation coefficient shows little differences between CL-NN and NN model results. These results show that cluster analysis and CL-NN model can be applied in the regional storm surge prediction and developed forecast system.

Development of Convective Cell Identification and Tracking Algorithm using 3-Dimensional Radar Reflectivity Fields (3차원 레이더 반사도를 이용한 대류세포 판별과 추적 알고리즘의 개발)

  • Jung, Sung-Hwa;Lee, GyuWon;Kim, Hyung-Woo;Kuk, BongJae
    • Atmosphere
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    • v.21 no.3
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    • pp.243-256
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    • 2011
  • This paper presents the development of new algorithm for identifying and tracking the convective cells in three dimensional reflectivity fields in Cartesian coordinates. First, the radar volume data in spherical coordinate system has been converted into Cartesian coordinate system by the bilinear interpolation. The three-dimensional convective cell has then been identified as a group of spatially consecutive grid points using reflectivity and volume thresholds. The tracking algorithm utilizes a fuzzy logic with four membership functions and their weights. The four fuzzy parameters of speed, area change ratio, reflectivity change ratio, and axis transformation ratio have been newly defined. In order to make their membership functions, the normalized frequency distributions are calculated using the pairs of manually matched cells in the consecutive radar reflectivity fields. The algorithms have been verified for two convective events in summer season. Results show that the algorithms have properly identified storm cells and tracked the same cells successively. The developed algorithms may provide useful short-term forecasting or nowcasting capability of convective storm cells and provide the statistical characteristics of severe weather.

Wave Responses of Buoyant Flap-typed Storm Surge Barriers - Numerical Simulation (부유 플랩형 고조방파제의 파랑응답 - 수치모의)

  • Jeong, Shin-Taek;Ko, Dong-Hui;Park, Woo-Sun
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.21 no.2
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    • pp.196-208
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    • 2009
  • In this paper, wave responses of buoyant flap-typed storm surge barriers was studied numerically. Wave motions were modeled by using a linear potential wave theory, and behaviors of structures were represented as a Newton's 2nd law of motion. The near field region of the fluid was discretized as conventional quadratic iso-parametric elements, while the far field was modeled as infinite elements. Comparisons with the results from hydraulic model tests show that the present model gives good results. By using the model, the applicability of a buoyant flap-typed storm surge barrier in Masan bay was investigated considering field environmental conditions.

Patterns of Water Level Increase by Storm Surge and High Waves on Seawall/Quay Wall during Typhoon Maemi (태풍 매미 내습시 해일$\cdot$고파랑에 의한 호안$\cdot$안벽에서의 수위증가 패턴 고찰)

  • Kang, Yoon-Koo
    • Journal of Ocean Engineering and Technology
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    • v.19 no.6
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    • pp.22-28
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    • 2005
  • We investigated the characteristics of the overflow/wave overtopping, induced by the storm surge and high waves in Masan bay and Busan Coast during Typhoon 'Maemi', which landed at the southeast coast of the Korean peninsula on September, of 2003, causing a severe inundation disaster. Characteristics of the water level, increase by the overflow / wave overtopping, were discussed in two patterns. One is the increase of water level in the region, located inside of a bay, like Masan fishing port, and the waves are relatively small. The other is in the open sea, in which the waves act directly, as on the seawall in Suyong bay. In the former region, the water level increase was affected by the storm surge, as well as the long period oscillation and waves. In Masan fishing port, about $80\%$ of the water level increase on the quay wall was caused by the storm surge. In the latter one, it was greatly affected by the wave run-up. In Suyong bay, about $90\%$ of the water level increase on the seawall was caused by the wave run-up.

A STATISTICAL STUDY OF MAGNETIC STORM RECOVERY PHASE: PRELIMINARY RESULTS

  • Lee, D.Y.;Hwang, J.A.;Min, K.W.;Lee, E.S.;Cho, K.S.;Kim, S.G.;Bae, S.H.
    • Journal of Astronomy and Space Sciences
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    • v.18 no.1
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    • pp.27-32
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    • 2001
  • A statistical study has been performed of the magnetic storm recovery phase using the Dst index for 102 storm events in the interval January 1996 to December 1998. In 43 cases (or 42%) out of our 102 events, the recovery phase exhibits fast recovery (kaking about 8 hours or less) at its initial stage or for the entire recovery period. Since this fast recovery can be explained by the fast charge exchange less of $O^{+}$ ions which mostly com from the ionosphere, and since a fraction of $H^{+}$ ions is of ionospheric origin as well, our statistical result supports the view that the source of ring current ions in many magnetic storms can be terrestrial.

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The Meteorological Disaster Analysis for the Natural Disaster Mitigation in the Korean Peninsula (자연재해 저감을 위한 한반도 피해 현황 분석)

  • Park, Jong-Kil;Choi, Hyo-Jin;Jung, Woo-Sik
    • 한국방재학회:학술대회논문집
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    • pp.319-322
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    • 2007
  • This study aims to find the characteristics of damage and states of natural disasters at the Korean Peninsula from 1985 to 2004. Using the data of Statistical yearbook of calamities issued by the National Emergency Management Agency and Annual Climatological Report issued by the Korea Meteorological Administration. we have analyzed the cause, elements, and vulnerable regions for natural disasters. Major causes of natural disaster at Korean Peninsula are four, such as a heavy rain, heavy rain typhoon, typhoon, storm snow, and storm. The frequency of natural disaster is the highest from June to September. The period from December to March also shows high frequency. The total amount of damage is high during the summer season(Jul.-Sept). The period from January to March shows relatively high amount of damage due to storm and storm snow The areas of Gangwon-do, Gyeongsangnam-do and Gyeongsangbuk-do are classified the vulnerable region for the natural disasters. By establishing mitigation plans which fit the type and characteristics of disaster for each region, damage from disaster can be reduced with efficient prevention activities.

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Application of Storm Runoff Model on Small Watershed by Finite Element Method (유한요소법에 의한 소유역 유출모형의 적용)

  • 최진규;손재권
    • Water for future
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    • v.25 no.3
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    • pp.97-104
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    • 1992
  • The distributed hydrologic models are widely applied to estimate the storm-runoff with spatial variability in watershed characteristics and rainfall pattern. This study was aimed to introduce the event-oriented storm runoff model using finite element method, and to try it's applicability on small watershed. Yeonwha watershed was selected and 14 storm events in 1991 were used for the finite element model, and the simulation results were compared with hydrologic quantities.

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Preliminary Study of Ionosphere for Global Navigation Satellite Systems (위성항법시스템 적용을 위한 전리층 기본 연구)

  • Yang, T.H.;Lee, Y.J.;Jun, H.S.;Nam, G.W.;Kim, J.
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.14 no.1
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    • pp.55-62
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    • 2006
  • Ionospheric signal delay is a critical factor for precision differential GNSS(Global Navigation Satellite Systems) applications such as GBAS(Ground-Based Augmentation System) and SBAS (Satellite-Based Augmentation System). Most concern is the impact of the ionospheric storm caused by the interaction between Solar and geomagnetic activities. After brief description of the ionosphere and ionospheric storm, ionospheric models for SBAS are discussed. History of recent ionospheric storms is reviewed and their impact on GNSS is discussed. In order to support Korean GNSS augmentation system development, a preliminary study on the regional ionosphere performed. A software tool for computing regional ionospheric maps is being developed, and initial results during a recent storm period is analyzed.

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